Fires shaped Mount Kilimanjaro’s unique environment. Now they threaten it

In October, Tanzanian firefighters faced several fires on Mount Kilimanjaro, the tallest mountain in Africa and the largest independent mountain in the world. The mountain and surrounding forests are part of the Kilimanjaro National Park, a UNESCO World Heritage Site in 1987. Andreas Hemp gives an overview of the mountain’s natural environment and the challenges it faces.

Gary Chartrand

Is this the first time that a fire of this magnitude has occurred? If there have been fires of this type before, what damage was done to the vegetation on the mountain and how long did it take to recover?

Fires are quite common in the higher parts of Kilimanjaro at the end of the dry season, around February-March and September to October. Fire can transform ground cover, but it also maintains it. Studies I did with colleagues (using 50,000-year-old records of buried pollen in the soil) showed that fires have always played a role in shaping the vegetation belts on the mountain.

For example, some species, such as the giant marmot (Dendrosenecio) have adapted to fire. Furthermore, without the fires that opened up the forests, many light-demanding species, such as the famous giant lobelias, would not be able to grow.
However, several severe fires have occurred on Kilimanjaro over the past few decades which have radically changed the land cover.

The fires of 1996 and 1997, years with unusually dry seasons, destroyed large areas of the former rainforest. These are typically humid forests in high altitude areas that create unique environments. The forest has been replaced by bushes. The vegetation has started to recover and bushes have sprung up, but it is far from a forest, which would take at least 100 years to grow without fire. Since these ancient forests have an important function of collecting fog water, the loss of these forests has a serious impact on the mountain’s water balance, much greater than the impact of the melting of glaciers, which is ecologically insignificant.

The impact of these earlier fires was much greater than the recent one, which “only” affected the forests and not the forests.

What kind of vegetation exists on Mount Kilimanjaro and how unique is it?

Due to its enormous height, Kilimanjaro has several distinct vegetation belts.

It is surrounded at the foot of the crops with a unique mix of agriculture, savannah and forest. This is home to very rich biodiversity as well as the tallest trees on the continent.

Higher up, between approximately 1,800 and 3,000 meters, a mountain forest belt surrounds the entire mountain. This is one of the largest forest blocks in East Africa.

Higher still, between 3,000 and 4,000 meters, there is a swath of moor typical of the high mountains of East Africa. This vegetation is composed of Erica, Protea, Stoebe and many other species of shrubs, many of which are endemic and present only in one or more mountains.

Erica bushes burn very easily, making this belt of vegetation particularly flammable. During humid periods without fire, the old forest can re-establish itself and expand to the treeline at 4000m. During periods of drought, with recurrent fires (natural or man-made), the forest belt contracts and the ericaceous belt expands.

What challenges does the natural mountain environment face and have there been significant changes over the years?

Over the past 150 years, the regional climate has become drier. This caused the mountain’s glaciers to shrink by nearly 90% of their previous extent. The drier climate is also a reason for an increase in the frequency and intensity of forest fires in the upper areas of Kilimanjaro, which affect the forests.

Most of these fires are set by people (like honey pickers who smoke bees), but these fires wouldn’t have been as devastating if the weather had been wetter.

There is an interaction between direct anthropogenic impacts (caused by people) and climatic ones.

Since 1911, Kilimanjaro’s human population has grown from 100,000 to over 1.2 million. This resulted in a huge loss of natural vegetation. Kilimanjaro is becoming an ecological island, isolated and surrounded by agriculture. During this time it lost 50% of its forest cover. In low-lying areas, this is mainly due to logging and clearing. In the highlands it is due to fires.

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